For the control of internal combustion engines, it is common to call on the determination of the energy of a signal that is representative of the engine knock, an analog signal produced for example by an accelerometer sensor mounted on the engine, so as to be able to act on control parameters such as, in particular, the spark advance position. For a long time, this energy has been determined by analog means, by filtering the signal from the sensor both using a time window within which the knock is likely to be produced (FR-2 571 141) and within a range of frequencies for the signal characteristic of this knock phenomenon, then by rectifying and integrating this filtered signal.
With the arrival of powerful digital processors on the market, new, essentially digital, methods have been developed.
From the prior art, for example from the document U.S. Pat. No. 5,400,644, an engine knock detection method is known in which the energy of the signal from the sensor is analyzed according to a first frequency spectrum assumed to be that of the knock and according to a second spectrum that is representative of the engine noise, and the presence of the engine knock is deduced from the comparison of these energies.